The present invention relates to a fluid valve and more particularly to a silent constant flow valve for use in a hovering system for an underwater vehicle.
Fluid flowing through a valve between differential pressure areas can generate extremely high noise levels. The problems attendant upon the generation of noise include not only the human reaction criteria of annoyance, damage to hearing and reduction in work efficiency, but also the effect on physical structure and equipment, such as structural fatigue and equipment malfunction. On ships, however, and particularly on submarines, the sounds generated by valves, are most objectionable as these sounds can be detected by an enemy and can compromise the security of a mission.
Heretofore, various devices have been used to control or reduce noise in pressure devices. Mufflers, attenuation chambers, absorption devices and noise insulators have been used with some success. Recently, there has been introduced several apparatuses for reducing the pressure of gaseous or liquid media flowing through a pipe or duct with minimum or greatly reduced generation of noise or unwanted sound. One such device is shown and described in U.S. Pat. No. 3,665,965, which issued May 30, 1972, to Hans D. Baumann. In this patented device, a plurality of low noise throttling plates are positioned in a fluid flow containing conduit. The low noise throttling plates are passaged by multiple small section orifices producing a high frequency pressure wave whose noise is more readily attenuated by the conduit.